Smart hybrid actuator

ABSTRACT

A smart hybrid actuator includes: a body open at one side thereof and having a space portion formed at the inside thereof to reciprocate a piston thereinto, a flow path space portion formed in a wall thereof to flow hydraulic oil therealong, and a cover portion formed at the other side thereof, into which a rod hole is penetrated; a driving motor for driving a hydraulic pump positioned inside the body; the piston extended to the outside from the rod hole of the cover portion in such a manner as to be reciprocated inside the body in the lengthwise direction thereof; and the hydraulic pump provided inside the body and driven by the driving motor, wherein the wall of the body has an inner peripheral wall, and the flow path space portion is formed in the wall of the body.

TECHNICAL FIELD

The present invention relates to a smart hybrid actuator, and moreparticularly, to a smart hybrid actuator configured in simple and smartways wherein no additional pipe along which hydraulic oil flows isneeded, thus reducing production cost and providing easy installation,and further, the space for installation is substantially reduced throughthe simple and smart configuration thereof, thus improving theutilization in the space for installation thereof.

BACKGROUND ART

Generally, an actuator, which is operated by using various kinds ofpower, is structurally different in accordance with the kinds of powerused. For example, the actuator is largely classified into an electricactuator, a pneumatic actuator, and a hydraulic actuator in accordancewith the kinds of power used.

The electric actuator rotates a motor with electric power throughmanipulation load of a valve generated by the friction with oil pressureto output a rotary force and a driving force therefrom. The pneumaticactuator makes use of compressed air or compressed gas to output adriving force through a cylinder or a vane motor, and the hydraulicactuator makes use of the physical energy of compressed oil.

A hydraulic pump mounted in the actuator is apart for converting themechanical energy supplied from the outside into pressure energy of oilfor operating a hydraulic system, and the hydraulic pump is largelydivided into a fixed delivery type hydraulic pump having a constantvolume of fluid pushed and a variable delivery type hydraulic pumphaving a variable volume of fluid pushed.

Among them, the fixed delivery type hydraulic pump has been disclosed inKorean Patent Registration No. 10-0509925. As shown in FIG. 1, theconventional fixed delivery type hydraulic pump 8 includes a housing 81,transfer rollers 82, a transfer tube 83 and a driving motor (not shown).The housing 81 having the shape of a cylindrical container has a throughhole formed at one side thereof so as to penetrate the rotary shaft ofthe driving motor thereinto. The transfer rollers 82 having the shape ofa cylindrical pipe have cylindrical grooves formed thereinto so as torotatably insert shafts thereinto. In this case, three shafts areerectedly mounted on a circular rotary plate (not shown). The transfertube 83 is made of a soft rubber tube and located between the innerperipheral surface of the housing 81 and the transfer rollers 82. Therotary shaft of the driving motor is passed through the through hole ofthe housing 81 to rotate the rotary plate and the three transfer rollers82.

Under the above-mentioned configuration of the conventional fixeddelivery type hydraulic pump 8, if the rotary shaft of the driving motoris forwardly rotated, the three transfer rollers 82 are forwardlyrotated around the rotary shaft, and the transfer rollers 82 on thecontacted portion between the outer peripheral surfaces of the transferrollers 82 and the transfer tube 83 compress and retract the transfertube 83, and the fluid inside the transfer tube 83 located in thesection between the neighboring transfer rollers 82 is sequentially andcontinuously discharged from the introduction side 831 of the transfertube 83 to the discharge side 832 thereof. Contrarily, if the rotaryshaft of the driving motor is reversely rotated, the three transferrollers 82 are reversely rotated around the rotary shaft, and the fluidinside the transfer tube 83 located in the section between theneighboring transfer rollers 82 is sequentially and continuouslydischarged from the discharge side 832 to the introduction side 831thereof.

By the way, the conventional fixed delivery type hydraulic pump 8 hassome limitations on increasing pumping capability, that is, onincreasing the amount of fluid discharged determining the capacity ofthe pump. So as to increase the amount of fluid discharged, that is, thediameter of the transfer tube 83 and the number of transfer tubes shouldbe increased.

If the diameter and flow path radius of the transfer tube 83 areextended, however, the radius of the housing 81 is accordinglyincreased, and if the number of transfer tubes is increased, the widthof the housing 81 is accordingly extended, so that the whole volume ofthe hydraulic pump is bulky. So as to increase the number of transfertubes, the transfer tubes are laid on each other along the lengthwisedirection of the rotary shaft, which causes the housing 81 to beincreased in volume along the lengthwise direction of the rotary shaftin proportion to the number of transfer tubes.

Accordingly, if the conventional fixed delivery type hydraulic pump 8 isapplied to a compact driving device, there is a limitation on theimprovement of the pumping capability thereof, which demands thedevelopment for a new hydraulic pump capable of improving the pumpingcapability through the increase of the amount of fluid discharged, whileoccupying a substantially small volume in a restricted space. Further,the conventional fixed delivery type hydraulic pump 8 has theintroduction side 831 and the discharge side 832 of the transfer tube 83arranged in the same direction as each other, so that the conventionalfixed delivery type hydraulic pump 8 cannot be applied to aconfiguration wherein the hydraulic pump is inserted into a structureclosed in the lengthwise direction thereof like a cylinder in such amanner as to have the introduction direction and the discharge directionof the fluid are arranged in the opposite direction to each other.

On the other hand, the conventional actuator has pipes along whichhydraulic oil flows to reciprocate a piston, thus increasing theproduction cost and making it hard to conduct the pipe installation andmaintenance. Furthermore, if the power source of the hydraulic oil ismalfunctioned, the whole system does not work, and besides, highprecision of control is impossible. Particularly, water leakage orpressure loss may be generated from the pipes exposed to the outside ofthe actuator.

DISCLOSURE Technical Problem

Accordingly, the present invention has been made in view of theabove-mentioned problems occurring in the prior art, and it is an objectof the present invention to provide a smart hybrid actuator that iscapable of allowing a flow path space portion to be formed inside a bodythereof, along which hydraulic oil for reciprocating a piston disposedinside the body is moved circulatedly, thus reducing the size and volumethereof to effectively utilize the space for installation and thusrequiring no additional pipes to remove the inconveniences of the pipeinstallation and repairing.

Technical Solution

To accomplish the above object, according to the present invention,there is provided a smart hybrid actuator comprising: a body open at oneside thereof and having a space portion formed at the inside thereof soas to reciprocate a piston thereinto, a flow path space portion formedin a wall thereof so as to flow hydraulic oil therealong, and a coverportion disposed at the other side thereof, into which a rod hole ispenetrated, a driving motor for driving a hydraulic pump positionedinside the body, the piston extended to the outside from the rod hole ofthe cover portion in such a manner as to be reciprocated inside the bodyin the lengthwise direction thereof, and the hydraulic pump providedinside the body and driven by the driving motor; wherein the wall of thebody has an inner peripheral wall, and the flow path space portion isformed in the wall of the body.

According to the present invention, preferably, the wall of the bodyincludes the inner peripheral wall and an outer peripheral wall, and theflow path space portion is formed between the inner peripheral wall andthe outer peripheral wall in such a manner as to be extended in themoving direction of the piston.

According to the present invention, preferably, the hydraulic pump islocated under the piston and driven in such a manner as to be connectedto a driving shaft of the driving motor.

Advantageous Effects

According to the present invention, the smart hybrid actuator has thebody having the flow path space portion formed at the inside thereof,along which the hydraulic oil flows, so that no additional pipes areneeded, thus reducing the space occupied for installation, and further,circulation is carried out inside the body, thus minimizing theinfluence of expansion or retraction, which depends on the heating ofthe hydraulic oil or external temperature, on the strokes of the piston.Additionally, no hydraulic pipes exist on the outside of the actuator,thus solving the problem that the actuator is defunctionalized due towater leakage or shock.

DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing a conventional fixed delivery typehydraulic pump.

FIG. 2 is a perspective view showing a fixed delivery type hydraulicpump applied to a smart hybrid actuator according to the presentinvention.

FIG. 3 is an exploded perspective view showing the fixed delivery typehydraulic pump applied to the smart hybrid actuator according to thepresent invention.

FIG. 4 is a sectional view showing the line A-A of FIG. 2.

FIG. 5 is top views showing the operations of various variations of thefixed delivery hydraulic pump applied to the smart hybrid actuatoraccording to the present invention.

FIGS. 6 and 7 are sectional views showing the smart hybrid actuatorhaving the fixed delivery type hydraulic pump according to the presentinvention.

BEST MODE FOR INVENTION

Hereinafter, an explanation on a smart hybrid actuator according to thepresent invention will be in detail given with reference to the attacheddrawings.

FIG. 2 is a perspective view showing a fixed delivery type hydraulicpump applied to a smart hybrid actuator according to the presentinvention, FIG. 3 is an exploded perspective view showing the fixeddelivery type hydraulic pump applied to the smart hybrid actuatoraccording to the present invention, FIG. 4 is a sectional view showingthe line A-A of FIG. 2, FIGS. 5 a to 5 e are top views showing theoperations of various variations of the fixed delivery hydraulic pumpapplied to the smart hybrid actuator according to the present invention,and FIGS. 6 and 7 are sectional views showing the smart hybrid actuatorhaving the fixed delivery type hydraulic pump according to the presentinvention.

Hereinafter, the vertical direction in FIG. 3 is referred to as “upperand lower direction”, “lengthwise direction”, or “axial direction”.

According to the present invention, as shown in FIGS. 2 to 4, a fixeddelivery type hydraulic pump 1 applied to a smart hybrid actuatoraccording to the present invention includes a tube 10, a housing 20 anda pressurizer 40. A reference numeral 30 in FIGS. 2 to 4 indicates adriving motor for driving the fixed delivery type hydraulic pump 1.

The tube 10 is made of silicone rubber or a flexible soft material andhollow at the interior thereof. One or more tubes are provided, anddesirably, even numbered tubes like two, four, six or eight tubes areprovided. This allows an amount of fluid discharged through thepressurization of the pressurizer 40 as will be discussed later tobecome regular and further allows the load applied to the pressurizer 40to be uniformly distributed. Four tubes 10 are provided in FIG. 3.According to the present invention, one or more tubes 10 may beprovided, but for the convenience of the description, the configurationwherein four tubes 10 are provided will be explained.

A first tube 10 a is open at both ends 11 and 12 thereof in the oppositedirections to each other and extended spirally from one end 11 towardthe other end 12 in the lengthwise direction thereof, so that a fluidflows along both ends 11 and 12 thereof in the lengthwise directionthereof. A second tube 10 b is extended spirally like the first tube 10a and spaced apart from one end 11 of the first tube 10 a with thedistance of 90° in the circumferential direction formed by the spiralradius of the first tube 10 a. As a result, one end 11 of the first tube10 a and one end of the second tube 10 b are located with the distanceof 90° on the same circle as each other. A third tube 10 c is extendedspirally like the first tube 10 a and located with the distance of 90°with respect to the second tube 10 b. A fourth tube 10 d is extendedspirally like the first tube 10 a and located with the distance of 90°with respect to the third tube 10 c. One ends of the first to fourthtubes 10 a to 10 d are located with the distance of 90° in thecircumferential directions thereof.

The first to fourth tubes 10 a to 10 d have the same shapes as eachother, while being arranged at one ends thereof with the distance of 90°in the circumferential directions thereof.

The housing 20 is located on the outside of the spiral radius formed bythe tubes 10 a to 10 d and surrounds the tubes 10 a to 10 d in such amanner as to be brought into contact with the outer peripheral surfacesof the tubes 10 a to 10 d. According to the present invention, thehousing 20 is provided to surround all of the upper, lower and sideportions of the tubes 10 a to 10 d. The housing 20 serves to radiallypressurize the tubes 10 a to 10 d at the inside or outside thereof,together with the pressurizer 40, thus making the tubes 10 a to 10 dretracted to cause the flow paths of the tubes 10 a to 10 d to beclosed. As a result, the housing 20 serves to pressurize the tubes 10 ato 10 d on the opposite side to the pressurizer 40 with respect to thetubes 10 a to 10 d, at the time when the tubes 10 a to 10 d arepressurized by the pressurizer 40. Furthermore, the housing 20 serves tofixedly support both ends 11 and 12 of each tube and at the same timeserves as a path through which the fluid discharged from both ends 11and 12 of each tube is gently discharged to the outside of the tubes 10a to 10 d.

The housing 20 includes a first cap member 21, a second cap member 22and a side peripheral wall member 23.

The first cap member 21 is provided at one end portion of the tubes 10 ato 10 d. The first cap member 21 having the shape of a circular platehas first through holes 211 formed in upward and downward directionsthereof with the distance of 90° on four locations thereon. The firstthrough holes 211 are coupled to one ends 11 of the tubes 10 a to 10 d,thus forming flow paths along which the fluid flows. Further, firstcoupling portions 213 are formed on the underside (toward the tubes 10 ato 10 d) of the first cap member 21 in such a manner as to beprotrudedly extended downwardly from the first through holes 211. Inmore detail, the first coupling portions 213 are formed on the positionscorresponding to one ends 11 of the tubes 10 a to 10 d and thus coupledto one ends 11 of the tubes 10 a to 10 d in such a manner as to beextended spirally like one ends 11 of the spiral tubes 10 a to 10 d.Further, the first cap member 21 has a first center hole 219 formed atthe center thereof so as to rotatably support a driving shaft 31 of adriving motor 30 as will be discussed later. An adhesive is applied tothe inner peripheral surfaces of the first coupling portions 213 or tothe outer peripheral surfaces of one ends 11 of the tubes 10 a to 10 d,and as shown in FIG. 4, one ends 11 of the tubes 10 a to 10 d areinserted into the first coupling portions 213 so that the tubes 10 a to10 d can be coupled to the first cap member 21. To the contrary, theadhesive is applied to the outer peripheral surfaces of the firstcoupling portions 213 or to the inner peripheral surfaces of one ends 11of the tubes 10 a to 10 d, and the first coupling portions 213 areinserted into one ends 11 of the tubes 10 a to 10 d so that the tubes 10a to 10 d can be coupled to the first cap member 21.

The second cap member 22 is spaced apart from the first cap member 21 inthe upward and downward directions thereof by a given distance andsurrounds the other side of the tubes 10 a to 10 d. The second capmember 22 having the shape of a circular plate has second through holes221 formed in upward and downward directions thereof with the distanceof 90° on four locations thereon. The second through holes 221 arecoupled to the other ends 12 of the tubes 10 a to 10 d, thus formingflow paths along which the fluid flows. Further, second couplingportions 223 are formed on the top of the second cap member 22 in such amanner as to be protrudedly spirally extended upwardly from the secondthrough holes 221. In more detail, the second coupling portions 223 areformed on the positions corresponding to the other ends 12 of the tubes10 a to 10 d and thus coupled to the other ends 12 of the tubes 10 a to10 d in such a manner as to be extended spirally like the other ends 12of the spiral tubes 10 a to 10 d. Further, the second cap member 22 hasa second center hole 229 formed at the center thereof so as to rotatablysupport the driving shaft 31 of the driving motor 30. An adhesive isapplied to the inner peripheral surfaces of the second coupling portions223 or to the outer peripheral surfaces of the other ends 12 of thetubes 10 a to 10 d, and as shown in FIG. 4, the other ends 12 of thetubes 10 a to 10 d are inserted into the second coupling portions 223 sothat the tubes 10 a to 10 d can be coupled to the second cap member 22.To the contrary, the adhesive is applied to the outer peripheralsurfaces of the second coupling portions 223 or to the inner peripheralsurfaces of the other ends 12 of the tubes 10 a to 10 d, and the secondcoupling portions 223 are inserted into the other ends 11 of the tubes10 a to 10 d so that the tubes 10 a to 10 d can be coupled to the secondcap member 22.

The first coupling portions 213 and the second coupling portions 223 aremade of silicone rubber or a flexible soft material like the tubes 10 to10 d, and further, they may be made of a metal material.

The side peripheral wall member 23 is located between the first capmember 21 and the second cap member 22 in such a manner as to be broughtinto contact with the outer peripheral surfaces of the tubes 10 a to 10d. The side peripheral wall member 23 is open at both sides thereof andhas the shape of a hollow cylinder whose inner peripheral surface isbrought into contact with the outer peripheral surfaces of the tubes 10a to 10 d. The tubes 10 a to 10 d and the pressurizer 40 are disposedinside the side peripheral wall member 23 in such a manner as tosurround the outer peripheral surfaces of the tubes 10 a to 10 d. Thetop and underside end peripheries of the side peripheral wall member 23are coupled to the first cap member 21 and the second cap member 22. Theside peripheral wall member 23 is separately made and thus coupled tothe first cap member 21 and the second cap member 22, and otherwise, theside peripheral wall member 23 is formed unitarily with any one of thefirst cap member 21 and the second cap member 22. The side peripheralwall member 23 pressurizes and contactedly supports the tubes 10 a to 10d at the inside and outside thereof, together with the pressurizer 40,which may be a separate member formed between the first cap member 21and the second cap member 22, and in some cases, the side peripheralwall member 23 may be an inner peripheral wall of a cylinder into whichthe hydraulic pump 1 is installed. According to the present invention,the above-mentioned structure of the side peripheral wall member 23 isjust one example, and therefore, of course, it is not limited thereto.

Any one or both of the first cap member 21 and the second cap member 22may be coupledly inserted into both side portions of the side peripheralwall member 23 in the upward and downward direction thereof.

The driving motor 30, which is a power source for rotating thepressurizer 40, has the driving shaft 31 disposed on one side thereof.The driving shaft 31 of the driving motor 30 is inserted into thehousing 20 and rotatably supported against the first center hole 219 andthe second center hole 229. The driving shaft 31 may be rotatablysupported only against the second center hole 229. The driving shaft 31of the driving motor 30 is disposed in a direction parallel to the axialdirection of the spiral cylinder formed by the tubes 10 a to 10 d. Thedriving shaft 31 of the driving motor 30 is passed sequentially throughthe second center hole 229 of the second cap member 22, a rotary body 41of the pressurizer 40 as will be discussed later, and the first centerhole 219 of the first cap member 21. The driving shaft 31 may be notextended to the first center hole 219. In this case, the first capmember 21 does not have the first center hole 219.

On the other hand, the driving motor 30 has a separate decelerator (notshown). A bearing is mounted into the second center hole 229 so that thedriving shaft 31 can be rotatably supported thereagainst.

The pressurizer 40 is disposed at the inside of the spiral radius rangeformed by the tubes 10 a to 10 d and pressurizes the tubes 10 a to 10 dat the inside of the tubes 10 a to 10 d, while being connected to thedriving shaft 31 of the driving motor 30 in such a manner as to berotatable around the driving shaft 31. The pressurizer 40 has a givenlength in a direction parallel to the lengthwise direction of thedriving shaft 31, that is, in the upward and downward direction thereofand pressurizes the inner peripheral surfaces of the tubes 10 a to 10 d.Accordingly, portions of the tubes 10 to 10 d located between thepressurizer 40 and the side peripheral wall member 23 are retractedlypressurized, and other portions thereof not located between thepressurizer 40 and the side peripheral wall member 23 remain without anyretraction. As a result, the fluid flows along the portions of the tubes10 a to 10 d where no retraction occurs, whereas the flow of the fluidstops along the retracted portions of the tubes 10 a to 10 d. Under theabove configuration, if the pressurizer 40 is rotated by means of thedriving motor 30, the retracted portions of the tubes 10 a to 10 d aremoved in the circumferential direction thereof to spirally move thefluid within the tubes 10 a to 10 d, so that the fluid is dischargedselectively to one ends 11 or the other ends 12 of the tubes 10 a to 10d in accordance with the rotational direction of the driving motor 30.

Thus, the tubes 10 a to 10 d along which the fluid is moved through thepressurization of the pressurizer 40 are spirally located in thelengthwise direction of the pressurizer 40, and even if the number oftubes is increased, an amount of fluid discharged is increased in thedefined volume of the tubes, thus substantially improving the pumpingcapability. Accordingly, the diameters, lengths and number of the tubesare appropriately adjusted to easily control the amount of fluiddischarged from the tubes.

The pressurizer 40 includes the rotary body 41 and pressurizing rollers42.

The rotary body 41 has a first support member 411, a second supportmember 412 and a post member 413. The first support member 411 and thesecond support member 412 are spaced apart from each other in the upwardand downward direction thereof in such a manner as to be located betweenthe first cap member 21 and the second cap member 22. The first supportmember 411 is located on the underside of the first cap member 21, andthe second support member 412 is located on the top of the second capmember 22 in such a manner as to be spaced apart from the first supportmember 411 in the lengthwise direction of the driving shaft 31.

The post member 413 is extended in the upward and downward directionsthereof in such a manner as to be connected at one side thereof to thefirst support member 411 and connected at the other side thereof to thesecond support member 412. The first support member 411 and the secondsupport member 412 are fixedly connected to the post member 413. Thedriving shaft 31 of the driving motor 30 is insertedly fixed into thepost member 413, and as the driving shaft 31 is rotated, the post member413 is rotated unitarily with the driving shaft 31. The driving shaft 31is inserted into the post member 413, and then, pins are inserted intothe sides of the post member 413, so that the post member 413 and thedriving shaft 31 can be rotated unitarily with each other. Otherwise,the post member 413 has a polygonal hole formed thereon, into which thepolygonal-shaped driving shaft 31 is inserted, so that the post member413 and the driving shaft 31 can be rotated unitarily with each other.Further, the post member 413 has a female spline formed on the innerperipheral surface thereof and the driving shaft 31 has a male splineformed on the outer peripheral surface thereof, so that the post member413 and the driving shaft 31 can be rotated unitarily with each other.

The first support member 411 and the second support member 412 arefixedly connected to the post member 413 in such a manner as to beextended in the radial directions thereof.

The pressurizing rollers 42 are disposed on both sides of the drivingshaft 31 around the driving shaft 31 with the distance of 180°. Eachpressurizing roller 42 is rotatably coupled at both ends thereof to thefirst support member 411 and the second support member 412 in such amanner as to be located between the first support member 411 and thesecond support member 412. First, through holes are formed on the firstsupport member 411 and the second support member 412 in the upward anddownward directions thereof, and next, one side both ends of thepressurizing rollers 42 are inserted into the holes on the first supportmember 411 and the other side both ends thereof are inserted into theholes on the second support member 412.

The pressurizing rollers 42 have given lengths in the axial direction ofthe spiral radius formed by the tubes 10 a to 10 d and serve topressurize one or more tubes in such a manner as to be brought intocontact with the inner peripheral surfaces of the tubes 10 a to 10 dwithin the range from one ends 11 of the tubes 10 a to 10 d to the otherends 12 thereof.

If the first coupling portions 213 and the second coupling portions 223are made of silicone rubber or a flexible soft material like the tubes10 to 10 d, the pressurizing rollers 42 have the axial lengths from oneends 11 of the tubes 10 a to 10 d to the other ends 12 thereof, andcontrarily, if the first coupling portions 213 and the second couplingportions 223 are made of a metal material, as shown in FIG. 4, thepressurizing rollers 42 have the lengths by which the first couplingportions 213 and the second coupling portions 223 are not pressurized.

The pressurizing rollers 42 have the shape of a cylinder and come intocontact with the tubes 10 a to 10 d at the inside of the spiral radiusformed by the tubes 10 a to 10 d. In this case, the flow paths in thetubes 10 a to 10 d are closed through the contact between thepressurizing rollers 42 and the tubes 10 a to 10 d. As the rotary body41 is rotated, the contacted portions between the pressurizing rollers42 and the tubes 10 a to 10 d are moved to allow the fluid within thetubes 10 a to 10 d to be squeezed, so that the fluid is moved upwardlyor downwardly along the flow paths of the spiral tubes 10 a to 10 d.

According to various variations of the present invention, on the otherhand, the pressurizer 40 has the pressurizing rollers 42 disposedradially around the driving shaft 31, and for example, two, three orfour pressurizing rollers 42 are disposed radially around the drivingshaft 31. Even if not shown, further, four or more pressurizing rollers42 may be disposed radially around the driving shaft 31. In this case,the four pressurizing rollers 42 are disposed in a circumferentialdirection around the driving shaft 31 with the distance of 90°.

Then, an explanation on the structures of the tubes according to thepresent invention will be in detail given.

As mentioned above, one or more tubes are provided, and the tubes 10 ato 10 d are spirally formed in such a manner as to be laid on each otherin the lengthwise direction of the pressurizer 40 (in the upward anddownward directions in FIG. 3). As the pressurizer 40 is rotatedforwardly or reversely, accordingly, the fluid within the tubes 10 a to10 d is moved upwardly or downwardly. One ends 11 of the tubes 10 a to10 d are located concentrically on the same plane as each other, andalso, the other ends thereof are located concentrically on the sameplane as each other.

FIG. 5 is top views showing the operations of various variations of thefixed delivery hydraulic pump applied to the smart hybrid actuatoraccording to the present invention, wherein the tubes are laid on eachother with the same diameters as each other, but for the convenience ofthe description, they are shown with different diameters from eachother.

FIG. 5 a shows the structure of the tubes according to the presentinvention, wherein four tubes 10 a to 10 d are arranged to have one endsand the other ends located with the phase difference of 360°. In thiscase, the pressuring rollers 42 pressurize the four tubes 10 a to 10 dat the same time over the whole section thereof, so that load isdistributedly applied uniformly to the pressuring rollers 42. If oneends and the other ends of the tubes 10 a to 10 d have the phasedifference of 360°, they are spaced apart from each other in the axialdirections thereof but they correspond to each other in thecircumferential directions thereof, so that the lines indicated radiallydenote the locations of one ends and the other ends of the tubes 10 a to10 d. The end portions of the four tubes 10 a to 10 d are spaced apartfrom each other with the distance of 90° in the circumferentialdirections thereof.

FIG. 5 b shows the structure wherein two tubes 10 a and 10 b arearranged to have one ends and the other ends located with the phasedifference of 360°. In this case, the pressuring rollers 42 pressurizethe two tubes 10 a and 10 b at the same time over the whole sectionthereof, so that load is distributedly applied uniformly to thepressuring rollers 42. If one ends and the other ends of the two tubes10 a and 10 b have the phase difference of 360°, they are spaced apartfrom each other in the axial directions thereof but they correspond toeach other in the circumferential directions thereof, so that the linesindicated radially denote the locations of one ends and the other endsof the tubes 10 a and 10 b. The end portions of the two tubes 10 a and10 b are spaced apart from each other with the distance of 180° in thecircumferential directions thereof. In this case, if a plurality ofpressurizing rollers 42 is equally spaced apart from each other in thecircumferential directions thereof, no eccentric load is applied to thepressurizer 40.

As shown in FIGS. 5 a and 5 b, a plurality of pressurizing rollers 42 isequally spaced apart from each other in the circumferential directionsthereof, no eccentric load is applied to the pressurizer 40. Further, iftwo or more pressurizing rollers 42 are equally spaced apart from eachother in the circumferential directions thereof, one pressurizing roller42 starts to pressurize the tubes before the other pressurizing roller42 stops the pressurization, thus serving as a pump.

FIG. 5 c shows the structure wherein the four tubes 10 a to 10 d arearranged to have one ends and the other ends located with the phasedifference of 180°, and FIG. 5 d shows the structure wherein the fourtubes 10 a to 10 d are arranged to have one ends and the other endslocated with the phase difference of 270°. In these cases, thepressuring rollers 42 pressurize the two or three tubes at the same timeover the whole section thereof, and accordingly, if a plurality ofpressurizing rollers 42 is equally spaced apart from each other in thecircumferential directions thereof, no eccentric load is applied to thepressurizer 40.

Further, if two or more pressurizing rollers 42 are equally spaced apartfrom each other in the circumferential directions thereof, onepressurizing roller 42 starts to pressurize the tubes before the otherpressurizing roller 42 stops the pressurization, thus serving as a pump.

On the other hand, FIG. 5 e shows the structure wherein the three tubes10 a to 10 c are arranged to have one ends and the other ends locatedwith the phase difference of 180°, and in this case, the pressurizingrollers 42 pressurize the two tubes at the same time over a portion ofthe whole section thereof, while pressurizing only one tube over theother portions thereof. Accordingly, load is not applied uniformly tothe pressuring rollers 42, and thus, eccentric load is applied to thepressurizer 40. Even in this case, however, if two or more pressurizingrollers 42 are equally spaced apart from each other in thecircumferential directions thereof, one pressurizing roller 42 starts topressurize the tubes before the other pressurizing roller 42 stops thepressurization, thus serving as a pump.

Even if not shown, four tubes may be arranged to have one ends and theother ends located with the phase difference of 90°, and in this case,one tube is pressurized by the pressurizing rollers 42 at the same time.

In conclusion, the number of tubes 10, the phase differences of thetubes 10, the diameters and lengths of the tubes 10 are adjusted toallow the amount of fluid discharged from the hydraulic pump 1 to beincreased, thus adjusting the pumping capability, and further, theadjustment factors of the tubes 10, as mentioned above, do not increasethe volume of the hydraulic pump 1, thus allowing the hydraulic pump 1to be embedded in a compact actuator. Further, the fluid introductiondirection and the fluid discharge direction of the hydraulic pump 1 arearranged in the opposite directions to each other, so that the hydraulicpump 1 can be appropriately installed into a cylinder extended with arelatively long length.

FIGS. 6 and 7 are sectional views showing the smart hybrid actuatorhaving the fixed delivery type hydraulic pump according to the presentinvention. The smart hybrid actuator 5 includes a body 51, a piston 531,the hydraulic pump 1, and the motor 30 driving the hydraulic pump 1.

The body 51 has a space portion formed at the inside thereof, into whichthe piston 531 as will be discussed later is reciprocated, and furtherhas a flow path space portion 515 formed in the wall thereof, alongwhich the fluid flows. The body 51 has the shape of a cylinder andincludes an inner peripheral wall 513 serving as the side peripheralwall member 23 of the hydraulic pump 1 and an outer peripheral wall 514formed on the outside of the inner peripheral wall 513. As shown inFIGS. 6 and 7, the flow path space portion 515 is formed between theinner peripheral wall 513 and the outer peripheral wall 514. The flowpath space portion 515 is extended in the moving direction of the piston531.

The body 51 is open at one side thereof and has a cover portion 512formed at the other side thereof, into which a rod hole 511 ispenetrated. Further, the piston 531 is extended to the outside from therod hole 511 of the cover portion 512 in such a manner as to bereciprocated inside the body 51 in the lengthwise direction thereof. Thehydraulic pump 1 is disposed inside the body 51 in such a manner as toallow the fluid to flow within the body 51 by means of the rotation ofthe driving motor 30, thus reciprocating the piston 531. In this case,the hydraulic pump 1 is located under the piston 531.

Referring briefly to the operation of the smart hybrid actuator 5 havingthe above-mentioned configuration, as shown in FIG. 6, if the drivingmotor 30 is rotated to operate the hydraulic pump 1, the fluid flowsalong the flow path space portion 515 in the direction of an arrow inaccordance with the rotational direction of the driving motor 30 andmoves downwardly from the hydraulic pump 1. After that, the fluid isdischarged upwardly from the hydraulic pump 1 by means of the pumping ofthe hydraulic pump 1 and moves the piston 531 upwardly. Contrarily, asshown in FIG. 7, if the driving motor 30 is rotated in the oppositedirection to the above-mentioned direction, the fluid between the piston531 and the hydraulic pump 1 is pumped downwardly from the hydraulicpump 1 and flows along the flow path space portion 515 in the directionof an arrow, thus moving the piston 531 downwardly.

According to the present invention, the fixed delivery type hydraulicpump 1 has the discharge direction and the introduction directionlocated in the opposite direction to each other in the axial directionthereof, and in the same manner as above, it has the discharge positionand the introduction position placed in the opposite direction to eachother in the axial direction thereof. Accordingly, the moving directionand the fluid discharge and introduction directions of the fixeddelivery type hydraulic pump 1 are the same as those in the smart hybridactuator 5 as shown in FIGS. 6 and 7, so that the fixed delivery typehydraulic pump 1 can be operatively mounted inside the body 51 of thesmart hybrid actuator 5.

While the present invention has been described with reference to theparticular illustrative embodiments, it is not to be restricted by theembodiments but only by the appended claims. It is to be appreciatedthat those skilled in the art can change or modify the embodimentswithout departing from the scope and spirit of the present invention.

INDUSTRIAL APPLICABILITY

According to the present invention, the body of the smart hybridactuator has the flow path space portion formed at the inside thereof,along which the fluid flows, so that no additional pipes are needed,thus reducing the space occupied for installation.

1. A smart hybrid actuator comprising: a body (51) open at one sidethereof and having a space portion formed at the inside thereof so as toreciprocate a piston (531) thereinto, a flow path space portion (515)formed in a wall thereof so as to flow hydraulic oil therealong, and acover portion (512) formed at the other side thereof, into which a rodhole (511) is penetrated, a driving motor (30) for driving a hydraulicpump (1) positioned inside the body (51), the piston (531) extended tothe outside from the rod hole (511) of the cover portion (512) in such amanner as to be reciprocated inside the body (51) in the lengthwisedirection thereof, and the hydraulic pump (1) provided inside the body(51) and driven by the driving motor (30); wherein the wall of the body(51) has an inner peripheral wall (513), and the flow path space portion(515) is formed in the wall of the body (51).
 2. The smart hybridactuator according to claim 1, wherein the wall of the body (51)comprises the inner peripheral wall (513) and an outer peripheral wall(514), and the flow path space portion (515) is formed between the innerperipheral wall (513) and the outer peripheral wall (514) in such amanner as to be extended in the moving direction of the piston (531). 3.The smart hybrid actuator according to claim 1, wherein the hydraulicpump (1) is located under the piston (531) and driven in such a manneras to be connected to a driving shaft (31) of the driving motor (30).